Conventionally, a shift range switch device controls the switching between a plurality of shift ranges in response to a driver's request for switching the shift ranges. For example, a system/controller described in patent document 1 below includes an output shaft sensor that detects a rotation angle of an output shaft engaged with a rotation shaft of a speed reduction mechanism for reducing a rotation speed of a motor.
(Patent document 1) Japanese Patent No. 4385768
The patent document 1 shows, as an example of the output shaft sensor, (i) a potentiometer that generates a linearly changing output voltage based on the rotation angle of the output shaft or (ii) a switch that turns ON at a position in a rotation angle range that corresponds to each of the shift ranges. In instances where the switch is used as the output shaft sensor for setting a target position of the motor based on the output of the switch, motor control may be affected due to an abrasive powder or an electrical noise that hinders a detection of the sensor signal edges.